I have a peltier modded T3i, and the sensor fogs up in the middle of the night. This started happening when I moved to a more humid Georgia. I tried using dew strips, but it seems as if the camera body opening is too thick and deep for the heat to get to the sensor. I thought about letting the cam shoot all night inside a sealed ziplock bag on the scope to see if that might make the air drier. Any ideas on what I can do to correct this issue?

Since you have a cold-finger camera, you don't need a cold box. Putting a box around the camera with desiccant in it won't help either. The desiccant will dry the air in the box, but the sensor is in the camera aiming out a tube which is exposed to the night air.

Putting a clear filter in front of the camera should do the trick. It will isolate the air in the camera from the outside air. You can then put a dew strap around the part where the filter is and that will keep the filter free of dew.